Performance: reuse existing semantic model on newer versions of Microsoft.CodeAnalysis

Author: Bart Koelman

src/CSharpGuidelinesAnalyzer/CSharpGuidelinesAnalyzer/Extensions/OperationExtensions.cs

@@ -1,4 +1,6 @@
-using System.Linq;
+using System;
+using System.Linq;
+using System.Reflection;
 using System.Threading;
 using JetBrains.Annotations;
 using Microsoft.CodeAnalysis;
@@ -11,6 +13,9 @@ namespace CSharpGuidelinesAnalyzer.Extensions
     /// <summary />
     internal static class OperationExtensions
     {
+        [CanBeNull]
+        private static readonly PropertyInfo OperationSemanticModelProperty = typeof(IOperation).GetRuntimeProperty("SemanticModel");
+
         [CanBeNull]
         public static IdentifierInfo TryGetIdentifierInfo([CanBeNull] this IOperation identifier)
         {
@@ -176,6 +181,18 @@ public static IMethodSymbol TryGetContainingMethod([NotNull] this IOperation ope
             return model.GetEnclosingSymbol(operation.Syntax.GetLocation().SourceSpan.Start) as IMethodSymbol;
         }
 
+        [NotNull]
+        public static SemanticModel GetSemanticModel([NotNull] this IOperation operation, [NotNull] Compilation compilation)
+        {
+            if (OperationSemanticModelProperty != null)
+            {
+                object[] emptyArray = Array.Empty<object>();
+                return (SemanticModel)OperationSemanticModelProperty.GetMethod.Invoke(operation, emptyArray);
+            }
+
+            return compilation.GetSemanticModel(operation.Syntax.SyntaxTree);
+        }
+
         private sealed class IdentifierVisitor : OperationVisitor<object, IdentifierInfo>
         {
             [NotNull]

src/CSharpGuidelinesAnalyzer/CSharpGuidelinesAnalyzer/Rules/MiscellaneousDesign/DoNotPassNullOnEventInvocationAnalyzer.cs

@@ -114,7 +114,7 @@ private static void AnalyzeEventInvocation([NotNull] IInvocationOperation invoca
         {
             if (operation is IConditionalAccessInstanceOperation)
             {
-                SemanticModel model = compilation.GetSemanticModel(operation.Syntax.SyntaxTree);
+                SemanticModel model = operation.GetSemanticModel(compilation);
 
                 if (model.GetSymbolInfo(operation.Syntax).Symbol is IEventSymbol eventSymbol)
                 {

src/CSharpGuidelinesAnalyzer/CSharpGuidelinesAnalyzer/Rules/MiscellaneousDesign/RaiseEventFromProtectedVirtualMethodAnalyzer.cs

@@ -97,7 +97,7 @@ private static IEventSymbol TryGetEventForNullConditionalAccessInvocation([NotNu
         {
             if (operation is IConditionalAccessInstanceOperation)
             {
-                SemanticModel model = compilation.GetSemanticModel(operation.Syntax.SyntaxTree);
+                SemanticModel model = operation.GetSemanticModel(compilation);
                 return model.GetSymbolInfo(operation.Syntax, cancellationToken).Symbol as IEventSymbol;
             }
 

src/CSharpGuidelinesAnalyzer/CSharpGuidelinesAnalyzer/Rules/Naming/UseUnderscoreForUnusedLambdaParameterAnalyzer.cs

@@ -69,7 +69,7 @@ private static void AnalyzeAnonymousFunction(SyntaxNodeAnalysisContext context)
         private static void AnalyzeParameterUsage([ItemNotNull] ImmutableArray<IParameterSymbol> parameters, [NotNull] SyntaxNode bodySyntax,
             SyntaxNodeAnalysisContext context)
         {
-            DataFlowAnalysis dataFlowAnalysis = TryAnalyzeDataFlow(bodySyntax, context.Compilation);
+            DataFlowAnalysis dataFlowAnalysis = TryAnalyzeDataFlow(bodySyntax, context.SemanticModel);
 
             if (dataFlowAnalysis == null)
             {
@@ -107,10 +107,9 @@ private static bool ConsistsOfUnderscoresOnly([NotNull] string identifierName)
         }
 
         [CanBeNull]
-        private static DataFlowAnalysis TryAnalyzeDataFlow([NotNull] SyntaxNode bodySyntax, [NotNull] Compilation compilation)
+        private static DataFlowAnalysis TryAnalyzeDataFlow([NotNull] SyntaxNode bodySyntax, [NotNull] SemanticModel semanticModel)
         {
-            SemanticModel model = compilation.GetSemanticModel(bodySyntax.SyntaxTree);
-            return model.SafeAnalyzeDataFlow(bodySyntax);
+            return semanticModel.SafeAnalyzeDataFlow(bodySyntax);
         }
 
         private static bool IsParameterUsed([NotNull] IParameterSymbol parameter, [NotNull] DataFlowAnalysis dataFlowAnalysis)